HP 664644-B23 is a 3X Node Server Tray component for ProLiant SL4540 Gen8 servers. The "9X5XNBD" designation appears to reference a support service level, though this specific service code could not be verified for this part number in official documentation.
3X Node Server Tray
ProLiant SL4540 Gen8 compatible
Rack mountable form factor
Supports three node configurations with dual-socket Xeon E5 v2 processors per node
